Why measuring antimatter is the key to our Universe (Synopsis)

Ethan

1 year ago

The galaxy cluster MACSJ0717.5+3745, must be made of matter just like we are, or there would be evidence of matter-antimatter annihilation along the line of sight. Image credit: NASA, ESA and the HST Frontier Fields team (STScI).

Antimatter is the counterpart to matter: it exists with the same mass, opposite charge, and if ever the two should touch, they annihilate away into pure energy via Einstein’s E = mc^2. But there are a great many properties of antimatter that we haven’t yet measured due to how much energy it takes to create it and how difficult it is to contain.

The particles and antiparticles of the Standard Model. Image credit: E. Siegel.

As we continue to make advances on this front, it’s important to keep in mind why we do it: antimatter must be fundamentally different from matter in some vital ways to create a Universe that’s filled with matter and not antimatter today. We’ve uncovered very few ways that these particles and antiparticles are different, and they’re so far insufficient to explain why our Universe is the way we observe it to be.

Trajectories of antihydrogen atoms from the ALPHA experiment. (Photo courtesy of Chukman So/University of California, Berkeley)